Market preview: Stock futures tick higher after the ADP jobs report pleasantly surprises, although don't expect it to say much about what the non-farm data will be like on Friday. The S&P Benchmark is +0.1%. MetroPCS -0.5% following confirmation that it's merging with T-Mobile USA, while Best Buy is +3.4% on speculation that Richard Schulze and P-E firms are doing their due diligence. Later: ISM Non-Manufacturing Index